The Nightmare Arena

The Ancients have awoken...
The Ancients, Old Gods, Creators of the Realms have awoken from their centuries of slumber. The Realms, four alternate realities each created in the image of its maker, pulse with power once more.
The Abyss

The Void

The Black Forest

The Silence

Now awake, The Ancients have resumed their war and we all must choose a side. Pick your realm and pledge your loyalty.
Choose your leader, build your deck of powerful minions and spells and take on the other realms and in doing so win the favor of your Ancient to avoid annihilation.

Begin each run by choosing your Realm and leader. Each with unique powerful abilities to build around. Throughout your journey you'll face powerful enemies from opposing realms, but after each battle you'll get to upgrade your deck and improve your chances of survival.
Collect new minions and spells

Upgrade existing minions and spells

Remove unwanted cards from your deck

Purchase powerful relics from the shop

Take on waves of increasingly difficult opponents in each encounter. Use your spells and minion abilities to keep your leader safe and eradicate the enemy. 
Positioning matters, make sure you position your minions to protect vulnerable ones and avoid devastating effects from opposing minions. Be careful though, opposing minions can move too, you'll have to anticipate their plan to avoid getting blown out.